As a freshman in the 2002 season, Dennis was a reserve behind a stable of experienced seniors including running backsJustin Fargas and Sultan McCullough as well as fullback/tailbacks Malaefou MacKenzie and Sunny Byrd; however, he did see play time in all 13 games, highlighted by a 38-yard touchdown run against rival UCLA. In 2003, he was the starting tailback in all 13 games over Reggie Bush and LenDale White. However, Dennis lost the starting spot for the 2004 season, having been suspended from the first two games due to a resulting criminal investigation and violating team rules. This allowed the tandem of White and Bush to emerge and relegate Dennis to the role of reserve for most of the season. Dennis did appear in a total of 9 games in the 2004 season, but was beset by a serious, season-ending torn knee ligament in practices before the 2005 Orange Bowl. During this period, Dennis considered transferring to another program, but his mother pressured him to stay and graduate as he is the only one of Teofilo’s children to have attended a university. The same torn knee ligament kept Dennis from participating in the entire 2005 season, having already used his redshirt year he lost a year of eligibility. Going into the 2006 season, Dennis was the leading career rusher among current student athletes. Unfortunately, in spring practice Dennis was again beset by season-ending knee injury, causing him to entirely miss a second year in a row. While this would have eliminated his final year of eligibility, Dennis and USC applied to the NCAA for a sixth year of eligibility, given the extreme circumstances. Dennis returned to full-contact practice in the 2007 spring practice In May 2007, Dennis graduated with his bachelor's degree in sociology. The NCAA granted his application for a sixth year of eligibility in June 2007. During his final game, the 2008 Rose Bowl game against Illinois, Dennis rushed for a touchdown, his first of the season and first since 2004, that led teammates to rush the goal from the sidelines in celebration. At the end of his six-year USC career, Dennis became the first player to play on six Pac-10 Championship squads. In addition to conference accolades, Dennis also made central contributions to teams that finished in the BCS top 5 during 6 consecutive seasons. With 70 wins in that span, Hershel Dennis is the "winningest player" in College Football history.
His father, Hershel Dennis, Sr., played running back for North Carolina A&T; his mother, who he calls "Mama Rose", would regularly attend her son's practices and is featured in a tattoo on his arm. Dennis has his initials tattooed on the back of his arms above the elbow. He has 3 kids Zion, Zirie & Zekiel. Dennis studied sociology as a RS Senior at University of Southern California. In addition to three high school championship rings, Dennis ended his college career with thirteen championship rings: six Pac-10 champion rings, two Orange Bowl champion rings, two Rose Bowl Champion rings, and two national championship rings. He is the cousin of Canadian Football League defensive lineman DeQuin Evans, and had been instrumental in obtaining permission for his cousin to sit in on classes at USC, enabling Evans to enroll in college and put his troubled youth behind him via a career in sports.